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N L Pace

Publications and source records attributed to N L Pace.

18 recordsLinked to original sources
PubMed1992

Technology assessment of anesthesia monitors.

This essay argues that optimal utilization of anesthesia monitors requires careful technology assessment. This careful assessment is important because monitors may produce spurious or uninterpretable values, or they may damage patients. In addition, resources should be spent only for truly beneficial devices. The types of evidence that this essay describes for use in technology assessment include questions concerning data reliability, data interpretability, and data outcome. Considerable evidence bearing on technology assessment has already been amassed. I propose synthesizing this evidence by meta-analysis. Additional primary studies of technology assessment are also needed.

Anesthesiology↗
PubMed1992

Iontophoretic delivery of morphine for postoperative analgesia.

Iontophoresis is a method of transdermal administration of ionized drugs in which electrically charged molecules are propelled through the skin by an external electrical field. This was a prospective, randomized, single-blind study to determine the effectiveness of iontophoretically delivered morphine HCl for the control of postoperative pain. Thirty-eight patients who underwent total knee or hip replacement completed this clinical trial. Informed consent was obtained before surgery and patients were instructed on the use of a patient-controlled analgesia (PCA) device. Postoperatively, pain in the recovery room was initially controlled with IV meperidine, and thereafter with PCA therapy using meperidine, 2 mg/cc, with a dose of 10 mg IV and a lock-out period of 15 min. The dose was adjusted as necessary and the lock-out period remained the same. The number of patient requests and the dose (mg) administered was recorded hourly. On the morning following surgery, iontophoresis devices were attached for 6 hr to patients who received either morphine HCl or lactated ringers solution. During this period and for 12 hr following completion of iontophoresis, PCA analgesia remained available to patients. Venous blood samples for determination of morphine levels were obtained every 30 min during iontophoresis, then every 60 min for 2 hr following iontophoresis. Of the 38 patients, 17 received iontophoresed morphine, and 21 received iontophoresed lactated ringers. The morphine group utilized the PCA device more than the control group during the baseline period. However, following the institution of iontophoresis and continuing up to 12 hr following completion of iontophoresis, the morphine group used significantly less PCA meperidine to maintain analgesia than the control group (p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Fentanyl and sufentanil increase intracranial pressure in head trauma patients.

Although opioids frequently are administered to patients with severe head trauma, the effects of such drugs on intracranial pressure are controversial. Nine patients with severe head trauma were studied for the effects of fentanyl and sufentanil on intracranial pressure (ICP). In all patients, ICP monitoring was instituted before the study. Full neuromuscular blockade was achieved with vecuronium bromide before the administration of either fentanyl (3 micrograms.kg-1) or sufentanil (0.6 microgram.kg-1) as an intravenous bolus over a 1-min period in a masked and random fashion. Patients received the other opioid in the same fashion 24 h later. Arterial blood pressure, heart rate, and ICP were recorded continuously for the 1 h after drug administration. Fentanyl was associated with an average ICP increase of 8 +/- 2 mmHg, and sufentanil with an increase of 6 +/- 1 mmHg. These increases were statistically significant. Both drugs produced clinically mild decreases in mean arterial blood pressure (fentanyl, 11 +/- 6 mmHg; sufentanil, 10 +/- 5 mmHg) that nevertheless were statistically significant. No significant changes in heart rate occurred. These results indicate that modest doses of potent opioids can significantly increase ICP in patients with severe head trauma.

Adult↗
PubMed1992

Anesthetic techniques during surgical repair of femoral neck fractures. A meta-analysis.

Fracture of the hip typically occurs in older women. These patients usually have serious accompanying chronic illnesses. There is a difference of opinion as to the choice of regional versus general anesthesia for surgery in these patients. This meta-analysis compared survival of patients with traumatic femoral neck fractures undergoing operative repair during regional or general anesthesia. The data sources were articles comparing regional and general anesthesia from peer reviewed journals. Thirteen randomized controlled trials were found. Besides 1-month mortality, variables used were estimated operative blood loss and the incidence of deep venous thrombosis. For dichotomous outcomes, two effect measures were calculated: the difference in probabilities and the odds ratio. For blood loss, a continuous variable, the effect measure was the mean difference in blood loss. A random-effects Bayesian meta-analysis was used to combine study data, estimate parameters and create 95% confidence intervals. Only the incidence of deep venous thrombosis was clearly greater for patients receiving general anesthesia, being 31 percentage points higher than for patients receiving regional anesthesia. By the odds ratio, deep venous thrombosis was almost four times more likely following general anesthesia. There was no difference in estimated operative blood loss. By probability difference, mortality was a non-significant 2.7 percentage points less following regional anesthesia. By odds ratio effect measure, death was 1.5 times more likely following general anesthesia, but the lower bound of the 95% confidence interval was close to 1. Meta-analysis does not allow a conclusion that important differences in mortality exist between regional and general anesthesia for traumatic hip fracture surgery.

Aged↗
PubMed1990

Cardiovascular effects of large doses of pentamorphone in the dog.

The cardiovascular effects of large doses of pentamorphone were evaluated in nine mongrel dogs basally anesthetized with sodium thiopental, 25 to 30 mg/kg, intravenously. All dogs were mechanically ventilated with 100% oxygen, and the PaCO2 was maintained between 35 and 40 mm Hg. Mean arterial pressure (MAP), central venous pressure, heart rate (HR), cardiac output (CO), pulmonary artery pressure, and pulmonary artery occluded pressure were measured, and stroke volume and systemic and pulmonary vascular resistances were calculated. Baseline measurements were obtained, then pentamorphone, 10 micrograms/mL, was given as an intravenous infusion at 2.5 micrograms/kg/min. Additional data were obtained after infusion of 25, 50, 75, 100, 125, 150, 200, 250, 300, and 350 micrograms/kg of pentamorphone. The inspired gases were then changed to 50% nitrous oxide in oxygen, and after a 20-minute equilibration period, an additional set of data was collected. Pentamorphone, 25 micrograms/kg, decreased HR 50%, MAP 65%, and CO 54%. No further changes in any measured or calculated variables were observed with additional doses of pentamorphone. The addition of 50% nitrous oxide to the inspired gas mixture had no effect on any measured or calculated hemodynamic variable. The minimal hemodynamic effects of pentamorphone in the dog suggest that further investigation into its use as an anesthetic is warranted.

Analysis of Variance↗
PubMed1979

Pharmacokinetics of naloxone and naltrexone in the dog.

The serum kinetics of 5 mg/kg of i. v. naloxone or naltrexone were studied in each of two groups of five dogs; serum samples were obtained from 2 min to 2 hr after injection. Serum concentrations were determined by radioimmunoassay. Serum levels of both naloxone and naltrexone fell rapidly; serum half-life during the elimination phase was 71.2 +/- 8.9 min (mean +/- S.E.) for naloxone and 85.1 +/- 9.0 min (mean +/- S.E.) for naltrexone. Although human and dog kinetics are similar for naloxone, naltrexone is long-acting in man, but is quickly dissipated in the dog.

Animals↗
PubMed1975

Indwelling pulmonary artery catheters. Their relationship to aspetic thrombotic endocardial vegetations.

To assess the incidence of aseptic thrombotic endocardial vegetations (TEV) after pulmonary artery catheterization with Swan-Ganz catheters we reviewed all autopsy reports for a two-year period in our hospital. In 413 autopsies there were five instances of aseptic TEV: 3 in 88 patients with Swan-Ganz catheters, 1 in 120 patients with central venous catheters, and 1 in the 205 patients without central vascular catheters. The incidence of TEV is significantly greater in patients with Swan-Ganz catheters than in other patients.

Adult↗
PubMedDate not supplied

Epinephrine-induced arrhythmias: effect of exogenous prostaglandins and prostaglandin synthesis inhibition during halothane-O2 anesthesia in the dog.

Prostaglandins (PG) modify sympathetic and parasympathetic neurotransmission and have antiarrhythmic properties. Inhibitors of PG synthesis sensitize the heart to certain experimentally induced arrhythmias. This study examined the arrhythmogenic dose (AD) of epinephrine in dogs during halothane-O2 anesthesia as modified by the infusion of PG and by treatment with an inhibitor of PG synthesis. Dogs were anesthetized with 1.25 MAC halothane. The AD of epinephrine was established by a series of 3-minute epinephrine infusions at 10-minute intervals. The AD of epinephrine was then redetermined during infusions of PG(PGE1--1 microgram/kg/min and PGF2 alpha--1 microgram/kg/min), after indomethacin, 3 mg/kg, and after aminophylline, 10 mg/kg. The AD remained unchanged from control during both of the PG infusions and following indomethacin. Only following aminophylline did the AD decrease significantly. Our study suggests that pretreatment of surgical patients with nonsteroidal antiinflammatory drugs which inhibit PG synthesis does not increase the likelihood of ventricular arrhythmias during halothane-O2 anesthesia.

Aminophylline↗
PubMedDate not supplied

Failure of naloxone and naltrexone to antagonize halothane anesthesia in the dog.

The effects of two narcotic antagonists, naloxone and naltrexone, on minimum alveolar anesthetic concentration (MAC) were studied during halothane anesthesia in the dog. Following induction of anesthesia, MAC was determined in duplicate. Each dog was then given one of the two narcotic antagonists and MAC was redetermined in duplicate: five dogs were given naloxone, 3 mg/kg IV, followed by an intravenous infusion of naloxone, 0.025 mg/kg/min; five dogs received naltrexone, 5 mg/kg IV. MAC was unaffected by the narcotic antagonists. Failure of narcotic antagonists to reverse halothane anesthesia suggests that the endogenous opioid peptides are not involved in the anesthetic state produced by halothane.

Animals↗